Recently, it has been demanded to develop an art for forming a metallic conductive film on an insulator film such as a flexible circuit board used in, for example, electronics, and an electromagnetic wave-shielding film used in plasma displays. Generally, for applying a metallic film thickly, an electroplating process is preferably employed in view of productivity, cost and easiness in controlling thickness. However, since a direct electroplating on an insulator film having a large surface resistivity cannot be effected, it is currently conducted that a thin metallic film is formed on an insulator film according to spattering method, vacuum deposition method or electroless plating method, thereafter electroplating is effected thereon to increase the thickness to a desired level.
For example, in patent document 1, a light-transmitting conductive film produced by utilizing a photosensitive material using a silver salt has excellent advantages such as a high transparency owing to its capability of precisely forming a fine line pattern and a mass production at a low cost compared with those according to other methods. However, in this film, a developed silver mesh has a high resistance and, therefore, an electroplating cannot be directly applied to the film. Thus, upon plating processing, the film requires a combination of electroless plating with electroplating.    Patent Document 1: JP-A-2004-221564